The present invention relates to a rotary compressor, particularly the structure of its cylinder block.
FIG. 11 is a conventional rotary compressor. A rotary-type compression mechanism 102 is housed in a hermetically sealed housing 101. The rotary-type compression mechanism 102 comprises cylinder block 103a, 103b, piston 104a, 104b, vane, rotary shaft 105, main bearing 107, and sub-bearing 108. The piston 104a, 104b eccentrically rotates in the cylinder. The vane moves reciprocally with its end being in contact with the end of piston 104a, 104b, dividing the cylinder into a high-pressure chamber and a low pressure chamber. The rotary shaft 105 drives the piston 104a, 104b. The main bearing 107 and sub-bearing 108 hold the axial end of cylinder block 103a, 103b therebetween, rotatably supporting the rotary shaft 105, and the main bearing 107 is positioned at motor 106 side and, the sub-bearing 108, at the opposite side of the motor. In the example of this conventional type, there are provided upper and lower compression elements, and the two compression elements are arranged with an intermediate plate 109 therebetween. The cylinder block 103a, 103b is made of cast iron. The compression mechanism 102 is secured to the hermetically sealed housing with the cylinder block 103a spot-welded thereto.
However, in such conventional rotary compressor, many processes such as making a number of holes and taps by machining cast iron and surface finishing are necessary to make cylinder blocks, resulting in higher costs. Particularly, in a two-cylinder rotary compressor, it is necessary to make two-cylinders, and in addition, the upper and lower cylinders are different in shape, adding to the cost of making cylinder blocks.
The present invention is intended to provide a compressor which is inexpensive and less in machining processes.
A rotary compressor of the present invention comprises a compression mechanism, a motor, and a hermetically sealed housing. The compression mechanism includes compression elements, a rotary shaft and bearing. The compression elements include a cylinder block, piston and vane. The cylinder block includes a cylinder hole and vane groove. The bearing closes the end of the cylinder hole and bears the rotary shaft. The compression mechanism and the motor are housed in the hermetically sealed housing. The cylinder block is made up of sintered metal. The compression mechanism is welded to the hermetically sealed housing within the region other than the cylinder block.
The method for manufacturing a rotary compressor of the present invention comprises the steps of:
(a) forming a sinter-molded blank for cylinder blocks by using sintered metal, and
(b) securing a compression mechanism to a hermetically sealed housing by welding the compression mechanism to the hermetically sealed housing in a region other than the cylinder block.
Preferably, the sintered metal is sintered iron.
Preferably, the cylinder block includes a first cylinder block and a second cylinder block, and the first cylinder block and the second cylinder block are formed by machining sinter-molded blanks identical in shape.
By this configuration, it is possible to reduce the machining processes and to make the blank parts usable in common, realizing the manufacture of a low-cost compressor. Further, the two cylinder blocks, the first cylinder block and the second cylinder block, may be die-formed by sinter molding, and it is possible to make the sinter-molded blanks identical in shape. Accordingly, it is possible to reduce the machining processes and to make the blank parts usable in common, thereby realizing the manufacture of a low-cost compressor.